This investigation involves two lines of research. In the first, taste receptor activation will be evaluated in the context of the allosteric model of Monod, Wyman and Changeux. The steady-state portion of the summated chorda tympani activity in rats is measured in response to several sodium and potassium salts, before and after inhibition by irreversible protein modification reagents. The data is analyzed by nonlinear least squares regression based on the appropriate allosteric equations. Secondly, glycosyltransferases from oral bacteria are being studied. Of particular interest are the kinetic mechanism, physical characteristics of the purified protein and effects of protein modification reagents on dextransucrase from Streptococcus mutans.